False accuse of me

Sir I have Got a number from internet for part time job in online.They said that they will give 10,000 captcha to complete in 10days and the amount will be given to me is 20,000 rupess and they asked my aadhar card as proof for the agrement i have send my aadhar card and my email adress and after that they send me a link which has got me a app named agrement maker and i have been instructed to do a digital singnature and a photo of to be uploades and after that they said that they will send the work and login details after 1 hour i called them but from 24 days i havent got any call from them and suddenly they called me today and said that i havent completed my given work i havent got any work mail from them and they even havent switched on there mobiles and now they are asking me to pay 12,500/-rs as penalty otherwise they are threating that they will go to court for justice.how to prove that i am innocent.They are also saying they will issue legal notice which i have pay a penalty of 1lakh can u please to give me a solution